High Current SS amps with input impedance = 200K


I'm looking to identify amps like this that would match optimally to an Audio Research sp16 tube pre-amp with output impedance of ~ 20K?
128x128mapman
Glai -- Wow! I looked at your system description, and I must say it is utterly magnificent. Congratulations!

As to why the Ref 3 did not give you the tight bass and the better transient response that the other two preamps do, I have no ideas to offer. What I can say is that I doubt it has anything to do with the somewhat higher output impedance of the Ref 3, considering that your interconnects are short, your power amp input impedance is reasonably high, and considering its outstanding reputation among many of our members, and the excellent reviews of it that I recall seeing.

Emerson -- Glad things seem to be shaping up. Again, there is no technical explanation that I can envision for the effects the Burson buffer stage seems to be having, and I doubt that it has any relation to the impedance issue this thread has focused on. As we all know very well lots of things in audio are both unexplainable and unpredictable.

Regards,
-- Al
As we all know very well lots of things in audio are both unexplainable and unpredictable. Almarg (Answers)

Al, I said practically the same thing in the "This Makes No Sense" thread.

All things occurring with the performance of audio systems are not guaranteed to make sense. If everything made sense, man would this be simpler. Foster_9

So our thinking is practically the same on the subject.
Yes, you can cross all the Ts and dot all the Is and there is still that mysterious place known as ..... The (audio) Twilight Zone....

Ominous music cue........
I've continued to research amp options for my system since my last postings here.

The bigger Class Ds that specifically address input impedance matching with tube pre-amps in general are still at the top of my list as a result of cost effectiveness, favorable reviews and commentary, specifications and small footprint and resulting impact on my current system layout and configuration.

The Bel CAnto ref 1000 mkiis (currently going for under $4000 used) would seem to be the holy grail in my case based on what I read and have gathered in lieu of hearing one.

The Wyred st-1000 ($2000 new, under that used) would appear to be the very close next best thing for significantly lower cost.

My impression is that the Wyreds and their ilk are driving down the resale value of the Bel Cantos and their historically pricier ilk (like SPectral and perhaps to a lesser extent Rowland).

Any comments on Wyred st-1000 versus BelCanto ref1000 mkii? I might be tempted to try the Bel Cantos at some point soon if further convinced that the sound differences justifies the cost premium?
Mapman, IMO the BC 1000M (formerly 1000 Mk.2) are likely to occupy the current price/performance sweet spot of moderately priced 500W ICEPOWER gamut. While I have not been able to listen to W4S in the same system as BC, the general impression of me preferring BC significantly and easily over W4S has been very consistent during several RMAF visits. Of course, BC 1000M is quite more expensive than W4S as well. . . and to make things just a little more exciting, W4S is said to be introducing soon reference level amplifiers based on ICEpower, which I have not heard yet. G.
Hello all.

Some closure on this for me finally. I ended up with a used pair of Bel Canto Ref1000 mkiis. They are up and running in my system. Very sweet indeed! I'll post some more impressions or whatever else might come up relating to these back in my system listing.

Thanks for all the feedback you all have provided to help me with this decision both here in this thread and elsewhere.
Mapman(or someone),

correct me if I'm wrong, but my perception has been that IcePower amps are not necessarily "high current" amps, being more of the voltage amplifier type.
Dark,

Not sure about a clear answer to your question.

The BC ref1000 specs indicate Peak Output Current: 45 amperes.

I've seen higher and lower. I suspect the switching nature of the power supply optimizes application of delivered current perhaps in comparison to other types?
In the particular case of the Bel canto Ref 1000 Mk.2s, the 'moderate' peak current of 45 amps is deceptively low. . . As the 1000 Mk.2s have a balanced output with active positive and negative leads on the speaker terminals, the current is roughly equivalent to a 90 Amp peak for a more common non balance output design, where the active signal would be relegated to the positive terminal, while the negative is left to float. I have used the Bel canto babies on my big Vienna mahlers v1.5s, and the authority that they yield is something to be beheld.

Enjoy them, Mapman! G.
Thanks Guido,

For some reason, whenever I read "high current" I always picture the pure Class A massive heatsink monsters from the late 80's/early 90's like the Class DR-3VHC, Levinson ML-2, Krell KSA-100, etc.

I guess that caused me to associate high current with high heat and huge size.
Guido -- While I certainly don't question your subjective comments, I don't think that the statement that 45 amps from a balanced amp output is roughly equivalent to 90 amps from unbalanced amp outputs is correct. If the spec is 45 amps (and btw I don't see that spec at the Bel Canto site), a maximum of 45 amps (plus whatever margin is built into the specification) would flow between the amp's red speaker terminal and black speaker terminal, regardless of whether both of those terminals are actively driven, or only one of them is actively driven.

The specs I do see are 500W into 8 ohms, 1000W into 4 ohms, and a rated minimum load of 2 ohms. If we assume that 2000W can be delivered into 2 ohms, that corresponds to a current of 31.6 amps.

Mapman -- Congratulations on the new amps! Enjoy!

Darkmobius -- As you realize, Class D technology is at the opposite end of the spectrum, relative to Class A, in terms of the amount of power that can be delivered relative to the amp's size, weight, and heat generation. Your characterization of them as "voltage amplifiers," though, is correct in the sense that they typically have extremely low output impedances (or, equivalently, very high damping factors). That allows them to deliver an output voltage which is directly proportional to input voltage regardless of load impedance, within the limits of their current capability (which in this case is very substantial).

Regards,
-- Al
Thank you Al, the figures of 40 to 45 Amps on peak current are inline with published specs for ICEpower 1000 ASP offerings from several other manufacturers. It is worth while pointing out that the 1000 ASP module is capable of yielding a more/less continuous output of 500W, hence the 30.1 Amps max continuous current you have calculated, while the peak current of 45A is sustained only in short bursts, hence the seemingly discrepant figures of peak current vs max power rating. Regards, G.
al,

the 45 amp spec is published in the amp's user guide on the bel canto website.
Mapman -- OK, I looked further and found the 45 amp peak current mentioned in this manual for the Ref1000M Version 1. It is not mentioned, though, in what I had been looking at, which was this manual for the Ref1000MkII.

In any event, I think that Guido's answer essentially settles the issue.

Best regards,
-- Al